1. Field of the Invention
This invention relates to a device for controlling tilting of a headrest in a treatment table such as for treatment of the teeth, eyes, ears, nose and the like, and more particularly to a device which is very easy for a user to operate and permits the efficient tilting of the headrest in such a manner as to enable backward and rearward tilting of the headrest by pushing in a support shaft in one direction which is transversely incorporated into a headrest base or a backrest base and to retain the headrest in a desired position by releasing the pushing force of the supporting shaft in the desired position.
2. Prior Art
Devices for controlling tilting of a headrest in a treatment table have heretofore been proposed in various types. For example, Japanese Utility Model Publication No. 3,193/70 filed previously by the present applicant or Japanese Utility Model Application No. 34,079/78 filed by another company are mentioned as a case in point, and the problem pointed out in common with the cited references is that parts incorporated as a means for tilting a headrest back and forth with respect to the backrest are relatively large in number and that no locking works when the backrest is tilted forward, namely, because the backrest is in the state of its being released from locking, a patient may be forced to bend down forward depending upon the posture in which he is treated. For example, in eye treatment, when a physician seated behind the backrest is treating the patient lying on the headrest and backrest inclined backward and if the physician happens to strike his knee against the headrest to thereby incline the headrest forward, the patient is caused to be subjected to a pain in his head due to deflection on the head and the physician also misses his aim. To mention other minor shortcomings, because a segmented rack is used in the prior art as one of the locking means, the pitch of teeth is relatively large and hence it is difficult to make fine adjustment of tilting. This invention is directed to improvements in the point mentioned above.